Life Sciences Commons^™

Using Spatial Methods To Analyse Anthropogenic Predation Risk And Movement Ecology Of White-Tailed Deer (Odocoileus Virginianus), Rhiannon D. Kirton

Electronic Thesis and Dissertation Repository

Hunting has been used as a central tool by wildlife managers to maintain populations of game species, however, we still lack a good understanding of exactly how hunting influences deer biology. Technological advances in GPS data over the last two decades now enable us to perform more detailed analysis on the effects of human hunters on wildlife populations. This research explores the spatial ecology of hunters and White-tailed deer in the Cross Timbers ecoregion of Oklahoma. Using new statistical methodologies to analyse simultaneous GPS tracking data on deer and hunters to study their spatial interactions. The results show how new …

Fear Of The Human "Super-Predator" In African Mammals, Nikita R. Frizzelle

Electronic Thesis and Dissertation Repository

Humans’ exploitive killing of virtually every mammal species globally may result in a perception of humans as feared, ultra-lethal predators. In Africa, mammals are central to the continent’s tourism industry; however, it is largely unknown whether African mammals fear the presence of tourists. Firstly, I aimed to review how the presence of humans on the landscape affects African mammal behaviour. Of 31 studies, most authors reported that humans alter mammal behaviour in a manner that may negatively impact survival. To test if a fear of humans can pervade communities, I simulated the presence of humans, hunting, lions, and birds using …

Elucidating The Structural And Dynamical Properties Of The Intrinsically Disordered Protein Nrf2 Using Molecular Dynamics Simulations, Megan Nicole Chang

Electronic Thesis and Dissertation Repository

The nuclear factor erythroid 2-related factor 2 (Nrf2) protein is a critical transcription factor for activating the antioxidant response pathway, a primary defense mechanism against disproportionate levels of oxidants in the cell, via the upregulation of cytoprotective genes. Notably, aberrant activation of Nrf2 in cancer cells increases their resistance to chemotherapy, rendering the treatment ineffective. The focus was to uncover the conformational landscape of Nrf2’s Neh4 and Neh5 domains, which participate in crucial interactions for complete transcriptional activation. Since Nrf2 is an intrinsically disordered protein (IDP), molecular dynamics simulations were employed to capture its dynamic nature and conformational heterogeneity. The …

Investigating Mycelial-Crop Residue Mat Application To Reduce Early-Colonizing Weeds In Row-Crop Agriculture, Donald T. Watson

Electronic Thesis and Dissertation Repository

Herbicide use within conventional agriculture has contributed to greatly increased crop yields since its widespread adoption, but environmental concerns regarding overuse and reliance on selective herbicides continue to mount. Using five fungal species and two crop residues in a factorial design, I created a novel slurry to control weeds through inhibition by the mycelial mat formed after application to soil. I monitored weed stem counts and the strength of the mycelial mat under the treatments. Additionally, as a proxy for crop yield, I measured the wet and dry mass of crop plant grown under application treatments. Weed prevalence was significantly …

Investigating The Role Of Pkc And Its Mechanisms In Regulation Of Igf-I Bioavailability In Fetal Growth Restriction, Allan W. Chen

Electronic Thesis and Dissertation Repository

Fetal growth restriction (FGR) is associated with decreased nutrient availability and reduced insulin-like growth factor (IGF)-I bioavailability via increased IGF binding protein (IGFBP)-1 phosphorylation. While protein kinase C (PKC) is implicated in IGFBP-1 hyperphosphorylation in nutrient deprivation, the mechanisms remain unclear. I hypothesized that the interaction of PKCα with protein kinase CK2β and activation of PKCα under leucine deprivation (L0) mediate fetal hepatic IGFBP-1 hyperphosphorylation. Parallel Reaction Monitoring Mass Spectrometry (PRM-MS) followed by PKCα knockdown demonstrated the PKCα isoform interacts with IGFBP-1 and CK2β under L0. Pharmacological PKCα activation with phorbol 12-myristate 13-acetate (PMA) increased whereas inhibition with bisindolylmaleimide II …

Understanding The Kinomic Contributions To Tyrosine Kinase Inhibitor Resistance In Triple Negative Breast Cancer, Cory Lefebvre

Electronic Thesis and Dissertation Repository

Resistance to tyrosine kinase inhibitors (TKIs) presents a growing challenge in the development of therapeutic targets for cancers such as triple negative breast cancer (TNBC), where conventional therapies are ineffective at combatting systemic disease. Potential targets in TNBC include the receptor tyrosine kinases EGFR (epidermal growth factor receptor) and c-Met, however, targeted anti-EGFR and anti-c-Met therapies have faced challenges in clinical trials due to acquired resistance. We hypothesize that response versus resistance of triple negative breast cancer to the tyrosine kinase inhibitors erlotinib and cabozantinib is mediated by compensatory changes in the kinome and phosphoproteome. To test this, we (1) …

Hibernation Is Super Complex: Dynamics Of Electron Transport System Supercomplexes, Amalie J. Hutchinson

Electronic Thesis and Dissertation Repository

The electron transport system complexes form supercomplexes (SCs) within mitochondrial membranes, perhaps increasing respiratory capacity or reducing reactive oxygen species production. My project aimed to determine the abundance, composition, and stability of SCs in a hibernator. Hibernators have dynamic metabolisms that change greatly during the winter. I isolated mitochondria from rats and thirteen-lined ground squirrels (TLGS) in different hibernation states and measured mitochondrial respiration. I extracted mitochondrial proteins using two detergents of different strengths, and quantified SC abundance using 2-dimensional gel electrophoresis and immunoblotting. Rats had fewer SCs than TLGS. SCs are dynamic in hibernation and the complex III composition …

Exercise As A Treatment For Cognitive Decline In Older Adults: The Role Of Growth Factors And Inflammatory Cytokines, Joshua A. Titus

Electronic Thesis and Dissertation Repository

The purpose of this thesis was to investigate the effects that exercise modalities have on neurotrophic and inflammatory blood markers and cognitive outcomes in older adults. A systematic review and meta-analysis were completed. The included studies illustrated that most of the literature evaluated the effect of aerobic exercise interventions on systemic concentrations of the blood marker brain-derived neurotrophic factor (BDNF). The review found that aerobic exercise increases BDNF and resistance training increases insulin-like growth factor 1 (IGF-1). Interventions with sex-specific cohorts presented advantages in males for blood marker and cognitive outcomes compared to females. One of three included interventions decreased …

Investigating A Novel Receptor That Mediates Vasoconstriction In Mouse Femoral Arteries, Joselia Carlos

Electronic Thesis and Dissertation Repository

The synthetic peptide trans-cinnamoyl-leucine-isoleucine-glycine-arginine-leucine-ornithine-amide (tcLIGRLO) causes smooth muscle contraction in mouse femoral arteries. The identity of the receptor that mediates this response is undetermined. We hypothesize that the novel mechanism for tcLIGRLO-induced contractions involves a G-protein coupled receptor (GPCR) and a G_q-Ca²⁺ signalling pathway. Chapter 2 describes experiments using femoral arteries isolated from male and female systemic protease-activated receptor 2 (PAR2KO) mice (n=31; 21 – 39 weeks of age) using tcLIGRLO and the G_q-inhibitor, YM-254890 (YM). Contractions produced by tcLIGRLO did not differ by sex but decreased as age increased. YM inhibited tcLIGRLO-induced contractions. Chapter …

The Study Of The Structure And Dynamics Of Parkin Activation, Elaine Aisha Freeman

Electronic Thesis and Dissertation Repository

Parkin is an RBR E3 ubiquitin ligase that has been implicated in both sporadic and familial Parkinson’s disease. Upon mitochondrial damage, parkin is activated step-wise to recruit and ligate ubiquitin to a substrate on the outer mitochondrial membrane. Disruption of this activation and ligation cascade is hypothesized to result in neuronal death related to Parkinson’s disease.

While structures of parkin for a number of these activation states exist, it is important to note they are not of full-length human parkin. These structures are often truncated and come from various non-human species to eliminate important, yet hard to quantify structural elements. …

Metabolic Regulation During Extraembryonic Endoderm Differentiation, Mohamed Gatie

Electronic Thesis and Dissertation Repository

The inner cell mass undergoes orchestrated cellular divisions resulting in the formation of the epiblast (EPI) and primitive endoderm (PrE). Understanding the process of cell fate specification is crucial to appreciate the intricacies of proper embryonic development. While the mouse embryo is an excellent model, limitations do exist with number, technical challenges, and accessibility, therefore, in my thesis I employed two cell-based models to recapitulate the EPI-PrE fate in vitro. Many signaling pathways have been implicated in this lineage decision, metabolism and its downstream products have been recently regarded as a driver of lineage commitment. Using various biochemical, molecular, …

Kindlin-1 Is Involved In Spreading, Migration, And Protein Regulation In Epidermal Scc-13 Cells, Naomi Mishan

Electronic Thesis and Dissertation Repository

Kindlin-1 is a scaffold protein linking the cytoskeleton to the extracellular matrix. Loss of function mutations in the FERMT1 gene (encoding Kindlin-1) cause gastrointestinal and skin defects associated with increased susceptibility to aggressive epidermal squamous cell carcinoma (SCC). This study investigated the consequences of targeted FERMT1 inactivation in the SCC-13 cell line of epidermal SCC. My studies demonstrate Kindlin-1 is not essential for SCC-13 proliferation or clonogenic potential in culture. Kindlin-1 was required for cell spreading on collagen I, but not on laminin-332, and its absence enhanced SCC-13 directional migration. Finally, I identified several proteins involved in tumor formation and …

Modeling Fetal Brain Development: A Semi-Automated Platform For Localization, Reconstruction, And Segmentation Of The Fetal Brain On Mri, Jianan Wang

Electronic Thesis and Dissertation Repository

With advances in fetal magnetic resonance imaging (MRI), research in neonatal neuroscience has shifted to identify in utero brain-based biomarkers for outcome prediction in high-risk fetuses, particularly those impacted by growth restriction. Volumetric segmentation of the fetal brain can provide better understanding of the trajectories of brain development and may aid in predicting functional outcomes. The current thesis aimed to develop semi-automatic methods to target deep brain structures in the fetal brain identified on MR images in fetuses with and without growth restriction. In this study, pregnant women (35-39 weeks gestational age [n=9]) with growth appropriate (n=8) and growth restricted …

Targeting Ccn Proteins In The Treatment Of Dermal Fibrosis, Alex Peidl

Electronic Thesis and Dissertation Repository

Fibrotic disorders, including the inflammatory connective tissue disease systemic sclerosis (SSc), contribute to 45% of deaths in the Western world. Currently there is no universally agreed-upon treatment for fibrosis. The CCN family of matricellular proteins are tightly spatiotemporally regulated proteins involved in development and wound healing, and are aberrantly expressed in fibrotic disease, including in SSc. CCN1 and CCN2 are overexpressed in SSc and contribute to the progression of animal models of fibrosis. CCN3 is reciprocally regulated to CCN1 and CCN2 and has been shown to suppress CCN2-mediated fibrogenic activity in kidney fibrosis. This led to the development of therapeutic …

Dopaminergic Modulation Of A Fast Visuomotor Pathway In Parkinson's Disease, Madeline C. Gilchrist

Electronic Thesis and Dissertation Repository

Parkinson’s disease (PD) is associated with reduced dopaminergic (DA) input to the dorsal striatum (DS). This study investigated the role of DA in modulating automatic, stimulus-driven reactions by assessing contextual control of stimulus-locked responses (SLRs) in 10 PD patients off and on DA medication. The SLR is the rapid recruitment of limb muscles that drives the arm towards suddenly appearing stimuli. Participants reached away from (anti-reach) or towards (pro-reach) a target on a screen, depending on instruction appearing 500 or 1000ms before target appearance. Modulation of SLRs was assessed by comparing SLR magnitude on anti- and pro-reach trials using surface …

Early Experience And The Functional Calibration Of The Stress-Response Systems, Niki Hosseini-Kamkar

Electronic Thesis and Dissertation Repository

Individuals exposed to adversities in childhood are at a greater risk of developing various diseases as adults, including cardiovascular disease and cancer (Felitti et al. 1998). These findings have sparked an interest in examining biological mechanisms that might explain the link between exposure to adversity and disease. To date, evidence has linked adversity to the function of the hypothalamic-pituitary-adrenal (HPA) axis. More recently, adversity has been associated with the function of the mesolimbic dopamine pathway as well.

This thesis uses a variety of techniques to explore the association between adversity and the function of the HPA axis and mesolimbic dopamine …

Neuroanatomical Characterization Of Fruitless P2 Neurons And Assessment Of Their Role In Female Mate Receptivity, William Yeung

Electronic Thesis and Dissertation Repository

In behaviourally isolated species, preferential mate choice for conspecifics over heterospecifics is a primary isolating barrier for reducing interspecific gene flow. Drosophila males court heterospecific females more frequently than females are sexually receptive to courting heterospecific males, emphasizing the importance of female mate preference in reproductive isolation. The neurogenetic bases of female mate preference have been elusive historically, but recent research identified the D. melanogaster fruitless (fru) P2 exon to influence both conspecific and heterospecific female receptivity. I have expanded on these findings by creating a transgenic line that expresses Gal4 under fru^P2 regulation. Driving a fluorescent …

Diversity And Drivers Of Oribatid Mites (Acari: Oribatida) In Boreal Peatlands, Carlos Rafael De Araujo Barreto

Electronic Thesis and Dissertation Repository

Boreal peatlands are important ecosystems for carbon cycling, storing 1/3 of the world’s terrestrial carbon in only ~3% of the globe, making them a key component of potential mitigation strategies in response to global climate warming. Experiments have shown that warming can affect plant and microbial communities in ways that potentially shift peatlands from carbon sinks to sources. Soil food webs, including the microarthropod community, are key in carbon cycling but are relatively understudied both in peatlands and under experimental warming. My research capitalized on a large-scale experimental field manipulation of warming in two contrasting peatland sites in Northern Ontario, …

A Behavioral Study On The Adult Marmoset Interference Control In Spatial Working Memory, Mohadese Khosravi Najafabadi

Electronic Thesis and Dissertation Repository

Interference control deficit in Working Memory (WM) is associated with neurodevelopmental disorders. The common marmoset (Callithrix jacchus) is an ideal non-human animal model for studying WM disorders. Previous studies of marmoset WM have used a touch-screen self-ordered sequencing task (SOST), which resembles an n-back paradigm and targets updating processes in internal interference control. However, the training time for the marmoset to reach proficiency on this paradigm is long given the short marmoset lifespan. In an attempt to accelerate marmoset learning of the task, we developed a new version of SOST that relied on foraging behaviour. The goal of …

Assessment Of Executive Function Using A Series Of Operant Conditioning Based Tasks In T1dm Rodents, Kevin T. Murphy

Electronic Thesis and Dissertation Repository

This study examined the impact of Type 1 Diabetes Mellitus (T1DM) on executive function using a series of operant conditioning based tasks in rats. Sprague Dawley rats were randomized to either non-diabetic (n = 12; 6 male) or diabetic (n = 14; 6 male) groups. Diabetes was induced using multiple low-dose streptozotocin injections. All diabetic rodents were insulin-treated using subcutaneous insulin pellet implants. At week 14 of the study, rats were placed on a food restricted diet to induce 5 - 10% weight loss. Rodents were familiarized and tested on a series of tasks that required continuous adjustments to novel …

Investigating Social Dynamics Using Automated Radiotracking Of Winter Flocks Of Black-Capped Chickadees (Poecile Atricapillus), Christopher J. Course

Electronic Thesis and Dissertation Repository

The major forces that govern social groups, namely fission-fusion dynamics, cohesion and maintenance, are nearly ubiquitous across animal groups. The field of animal collective behaviour has recently been married with automated radiotracking producing a ‘re-wilding’ of field research into sociality. The combination of this with Social Network Analysis has led to discoveries such as population wide information transfer and the flexibility of animal groups to change social connectivity based on environmental context. However, these networks are constructed, and do not include the dynamic environmental, spatio-temporal, and social contexts which directly affect sociality. I conducted the first automated radiotracking study I …

Insights Into O-Glcnac-Mediated Regulation Of Galectin Expression And Secretion In Promyelocytic Hl-60 Cells, Adam J. Mctague

Electronic Thesis and Dissertation Repository

Galectins are a family of -galactoside-binding proteins involved in cell stress responses and differentiation. Galectins are multifunctional proteins widely studied in many cell models including acute myeloid leukemia HL-60 cells where they mediate numerous intra- and extracellular functions in response to many stress-inducing stimuli. O-GlcNAcylation is a dynamic post-translational modification implicated in the regulation of many cellular diseases including cancers. The O-GlcNAc mediated expression and secretion of galectins during neutrophilic differentiation was examined in HL-60 cells. Galectin gene (LGALS), galectin protein expression, and galectin secretion were determined by RT-qPCR, immunoblotting, and ELISA, respectively. Inhibition of O-GlcNAcylation induced markers of differentiation …

Direct Electrical Stimulation Of Prefrontal Cortex Modulates The Transient Heart Rate Response To Exercise In Conscious Humans, Bartek Kulas

Electronic Thesis and Dissertation Repository

Prefrontal cortical regions play an essential role in generating appropriate cardiovascular adjustments, particularly in cardio-vagally mediated heart rate (HR) responses to active tasks. Functional imaging studies provide correlational evidence that this region coordinates HR responses to exercise, however, direct experimental evidence of prefrontal cortical HR regulation in humans is not available. Seven persons with epilepsy implanted with intracranial electroencephalography (iEEG) completed 2-second isometric handgrip (IHG) contractions at no-stimulation (NO-STIM) or sham-stimulation (SHAM) conditions, and during direct electrical stimulation (STIM) of the orbitofrontal and medial prefrontal cortex. HR responses to IHG during NO-STIM and SHAM increased HR by Δ4.9±2.7 bpm, compared …

Developing A Toolbox To Engineer Quantitative Trait Variation In Legume Species Using Crispr/Cas Technologies., Petar Miletic

Electronic Thesis and Dissertation Repository

The impact of intensive agriculture on the environment is immense. This is especially dire with regard to the natural nitrogen (N) cycle, where the human driven interference, primarily associated with industrial fertilization, has reached unsustainable levels. Unlike cereals, legumes, such as soybean, alfalfa and common bean, have the ability to use atmospheric nitrogen, which limits the need for industrial fertilization. A more wide-spread use of legumes could alleviate some of the negative impacts on the biogeochemical cycle while also providing a useful alternative to meat consumption, an important factor in sustainability. To reach this goal, further improvements of legume crops …

Long-Term Vs. Short-Term Plant Responses To Warming And Nitrogen Addition In A Temperate Old Field, Breanna Craig

Electronic Thesis and Dissertation Repository

Climate warming and atmospheric nitrogen (N) deposition are expected to have strong effects on plant productivity in temperate ecosystems over the next century. However, short-term experiments may not adequately address their potential effects because of lags in changes in species composition. I added new plots to a pre-existing field experiment to compare the short-term (1-2 year; new plots) vs. long-term (14-15 year; old plots) effects of warming and N addition on plant productivity, relative species abundances, plant tissue N content, and litter decomposition. In 2020, N addition increased aboveground plant productivity most in old plots and only increased belowground biomass …

Validation Of Arterial Spin Labeling For Longitudinal Monitoring And Differential Diagnosis Of Frontotemporal Dementia, Tracy Ssali

Electronic Thesis and Dissertation Repository

Frontotemporal dementia (FTD) is a devastating neurodegenerative disease characterized by a rapid decline in behavioural, language, and motor abilities. Advances in the understanding of FTD genetics and pathophysiology, and the subsequent development of novel disease modifying treatments have highlighted the need for tools to assess their efficacy. While structural magnetic resonance imaging (MRI) and functional imaging with ¹⁸F-flurodeoxyglucose (FDG) positron emission tomography (PET) are used for clinical diagnosis, structural changes are subtle at the early stages and PET imaging is expensive and access limited. Given the coupling of cerebral blood flow (CBF) to energy metabolism, an attractive alternative is …

Phase Imaging For Reducing Macrovascular Signal Contributions In High-Resolution Fmri, Olivia W. Stanley

Electronic Thesis and Dissertation Repository

High resolution functional MRI allows for the investigation of neural activity within the cortical sheet. One consideration in high resolution fMRI is the choice of which sequence to use during imaging, as all methods come with sensitivity and specificity tradeoffs. The most used fMRI sequence is gradient-echo echo planar imaging (GE-EPI) which has the highest sensitivity but is not specific to microvasculature. GE-EPI results in a signal with pial vessel bias which increases complexity of performing studies targeted at structures within the cortex. This work seeks to explore the use of MRI phase signal as a macrovascular filter to correct …

Motor Unit Firing Rate Control Of Agonist Skeletal Muscle During Voluntary Isometric And Shortening Contractions With Limb Movement, Eric A. Kirk

Electronic Thesis and Dissertation Repository

Voluntary movements throughout mammalian lifespan require skeletal muscle contractions that are controlled by time- and recruitment-dependent firing rate patterns. Single motor unit (MU) activity reflects the final efferent neural drive to the muscle, yet the underlying neural control of movement at the MU level is not well understood. Using intramuscular electromyography single MU recordings, relationships between voluntary contraction kinematics and MU firing rates were evaluated in vivo, in groups of young and older adult participants.

The purpose of study one was to characterize how MU firing rates are differently scaled among muscles relative to voluntary contraction intensity. Across 12 …

The Expression Of Guilt, Chloe A. Stewart

Electronic Thesis and Dissertation Repository

Though aversive, the experience and expression of guilt is important to healthy social functioning. Guilt is often described as visceral, and nonverbal guilt expressions are anecdotally observed, yet much remains unknown about how guilt is expressed. The present work aimed to explore the visceral experience of guilt via the autonomic nervous system (ANS), and the nonverbal display of guilt via facial, gestural, and postural expressions. Using a novel film paradigm, we explored ANS activity during guilt in healthy adults and adults with neurodegenerative disorders (NDs). We further explored the nonverbal behaviours associated with guilt in healthy adults. We hypothesized that, …

Metschnikowia Mitochondria, Dong Kyung Lee

Electronic Thesis and Dissertation Repository

Mitochondrial genomes are known for their diverse characteristics and are an attractive model to study genome evolution. Draft nuclear genomes of 71 Metschnikowia yeast strains are publicly available but their mitochondrial genome assemblies are incomplete, thereby making genome studies difficult. To remediate this shortcoming, complete mitochondrial genomes of 71 Metschnikowia strains were assembled from the draft nuclear genomes. Metschnikowia mitochondrial genomes exhibit an unprecedented amount of diversity, particularly with respect to the frequency and distribution of introns, which is often reflected upon overall genome size variations. Additionally, loss of synteny between strains of the same species further strengthens the notion …